1. Field of the Invention
The present invention relates to a zoom lens optical system, and more particularly, to a compact zoom lens optical system and a driving method of the same, which is applied to a small-sized system using electronic image sensing devices, such as charge coupled devices (CCDs) or complementary metal oxide semiconductor (CMOS) devices.
2. Discussion of the Related Art
Among optical systems needed to have compact sizes, those for mobile/potable devices should be further small-sized.
Especially, to make such a small optical system that is able to be mechanically set up while maintaining its performance and magnifying capacity, the optical system, beneficially, comprises an optical element including a reflective surface that reflects an optical path. The optical system, in which the optical path is bent at a right angle by the reflective plane, may be set up to a small device, and thus a size of the device can be further effectively decreased.
By the way, in a trend of miniaturizing mobile devices, to adopt a zoom lens optical system including a reflective surface in the mobile device, the optical system may have high resolution despite its small size as well as an optical overall length and a device size may be remarkably decreased.
In general optical systems, a zoom optical system that has performance of mega lens resolution and small size is a four-group zoom system, and, in the optical system, generally, second and third lens groups move to change zoom magnification, and a fourth lens group moves to adjust a focus.
However, the optical system has a disadvantage that it has high resolution at a specific object distance. This is why it is hard to correct aberration for other object distance because a lens group for zooming and a lens group for focusing are disposed at the same side with respect to a stop in the optical system.